1. Field of the Invention
The present invention relates to a shift knob for a shift lever of an automatic automotive transmission. More specifically, this invention relates to such a shift knob which obviates unsightly shrink marks and improves production efficiency.
2. Description of the Relevant Art
Japanese Utility Model No. 4-3149 discloses a conventional shift knob construction wherein a skeleton structure, which is made of a hard resin, is molded to form a one-piece body with a soft outer covering. However, this outer covering inevitably has portions which vary considerably in thickness. This variation induces a drawback that the thicker portions tend to shrink more than the thinner portions and thus gives rise to the so-called molding sink which impairs the appearance and aesthetic qualities of the shift knob.
Japanese Utility Model Preliminary Publication No. 4-93558 discloses an arrangement which has been proposed in an attempt to overcome the above-mentioned drawback. In this arrangement, the knob has a skeleton structure which is made of a hard resin and which is divided into two parts, i.e., a front half and a rear half, which can be assembled together by snapping one into the other or by means of screws. The assembled structure is then covered with a soft outer layer.
The two halves in this arrangement exhibit a thin-walled construction and provide a space between the two halves when assembled together. While this construction allows the respective halves to be of a thin-walled construction, it induces the drawback that, when the outer covering is formed, liquid resin is apt to wastefully leak between the two halves into the enclosed space.
The present invention was been developed in view of the aforementioned drawbacks and provides a shift knob which enables good production economy while also preventing the formation of shrink marks in the soft outer covering which detract from the appearance of the completed shift knob.